Aims and objectives
To assess a feasibility of ultrasound elastography for monitoring of conservative therapy of the varicose veins of lower extremities with a drug containing micronized purified flavonoid fraction (MPFF).
Ultrasound elastography, as a technique evaluating the elastic properties (stiffness) of tissues, was carried out after standard ultrasound examination. The elasticity of biological tissue describes its ability of reversible deformation, i.e. the property to exert mechanical resistance when the force is applied and to regain the original shape after removal of force. Elastography image is a graphical representation of the displacement of tissue layers under the influence of several cycles of compression/decompression of the investigated vein by sensor. The received echo signal is processed by the device, and the color-coded information on the displaceability of the studied tissue layers is displayed.
The dense tissue is indicated in blue, the tissue with moderate elasticity - in green and yellow-green, and softer tissue - in red.
According to our data, the unaltered vein has a soft-elastic structure of the vessel wall/perivasal tissues complex, which is uniformly encoded in green or yellow-green. The width of soft-elastic limbus around the vein is determined by the size of the vessel, as well as the presence of abnormalities. During the USEG of veins and adjacent tissues we evaluated the area of perivasal tissues on the posterior wall of the vessel at the moment of maximal decompression, which has a homogeneous elasticity, as well as the width of perivasal zone of tissue elasticity (Figures 1a, 1b). The vein is coded in red as the softest structure because of the presence of liquid component and formed elements that can move and, therefore, determine a high degree of relative elasticity of the tissue.
The study has shown that the changes identified using the ultrasound elastography are more pronounced in the vessels of large diameter. Intact veins of lower extremities have a homogeneous image of elastogram, suggesting about unaltered histological structure of these tissues. In the presence of varicose transformation, the heterogeneous elastography pattern reflected, probably, the disturbance of histological regularity of tissues surrounding the vessel.
The therapy with MPFF was associated with a trend to normalization of elastographic image of vessel, which relates to the reduction of the severity of aseptic inflammation and normalization of cellular structure, and, therefore, the physical properties of the studied tissue.
The obtained data confirm the feasibility of ultrasound elastography for identification of the objective markers of treatment response to MPFF in varicose disease.